Production of carboxylic amides has previously been accomplished by the reaction of a carboxylic acid with large excesses of amine. As a result, previous production methods are unfavorable economically and environmentally, requiring either expensive scrubbing and recovery equipment, or release of excess amine into the environment.
For example, GB 2,160,421 discloses a method for preparing stearamidopropyl dimethylamine by reacting 270 parts stearic acid with 100 parts dimethylamino propyl amine, under pressure, at a temperature of 140.degree. C. to 150.degree. C. for three hours. The reaction temperature is then increased to 165.degree. C. to 170.degree. C. and held for one hour completing the reaction. Expensive separation apparatus is suggested when high yields are desirable.
JP 3060957-A discloses the preparation of fatty acid bisamides by reacting fatty acid with a diamine at a molar ratio of 1.85-2.1:1 wherein the reaction temperature is 150-300.degree. C. The reaction is initially conducted under pressure (7-30 kg/cm.sup.2) and when the conversion to fatty acid bisamide reaches 85-95 wt % based on the diamine, the reaction system is returned to normal pressure.
JP 6 279 375-A discloses a method for the preparation of carboxylic acid amides that uses pressure but also uses expensive separation equipment for water removal and also uses large excesses of amine.
It would be desirable to produce carboxylic amides without the need for expensive recovery equipment, while removing the necessity of releasing excess amine into the environment.